Remotely operated clamping mechanisms for connecting and preloading members in end-to-end relation normally use hydraulically actuated annular piston arrangements or arrangements of a series of pistons to actuate the loading devices for tightening and preloading. For example, U.S. Pat. No. 4,114,928 discloses the use of manually actuated screws and hydraulic-operated pistons to control locking and toggle members. While hydraulic piston-operated clamping mechanisms have been generally accepted for connecting members there are disadvantages associated when such clamping mechanisms are used for connecting fluid conducting or drilling members for wells. For example, the members can become loose or actually disengage with the failure of hydraulic pressure. Moreover, hydraulic pistons held under pressure for extended periods of time are sometimes difficult to disengage so as to release the members; therefore, emergency mechanical backup systems, which are difficult to operate, are required to break apart the members.
Another type of prior art connection uses a cam means to engage a gripping surface with the end flange(s) of a pipe(s), as exemplified by U.S. Pat. Nos. 2,645,506 and 3,026,128. However, a problem with these designs is that the cam actuation is not capable of providing either horizontal or vertical movement to radially advance a toggle assembly. In addition, the existing designs fail to disclose a toggle assembly which is capable of locking in two members to permit a high make-up force.